1. Field of Invention
The present invention relates to coating technology.
2. Description of Related Arts
At least three rotating parts, i.e., a feed roller, a cooling roller, and a spreading roller which must cooperate to work accurately are necessary in coating process. Since the matrix membrane is very thin and weak, if the three rotating parts make mistakes on the feed rates, the matrix membrane will be torn easily. It is very difficult to accurately control the feed rates of the three rotating parts to completely synchronize with each other. Complicated mechanical structures and automation system are required to synchronize the feed rates, which causes increasing of the cost.
In addition, in the conventional vacuum coating equipment, the vacuum pump is ordinarily diffusion pump. The diffusion pump has disadvantages of high energy consumption, long starting time, low vacuum degree, etc. The energy consumption of the diffusion pump accounts for a large part of the energy consumption of the whole vacuum coating equipment.